#pragma once
#include<assert.h>
namespace jxh {
	template<class T>
	class vector {
	public:
		typedef T* iterator;
		typedef const T* const_iterator;
		vector() {};
		vector(const vector<T>& v) {
			reserve(v.capacity());
			for (const auto& e : v) {
				push_back(e);
			}
		}
		template <class InputIterator>
		vector(InputIterator first, InputIterator last) {
			while (first != last) {
				push_back(*first);
				++first;
			}
		}
		vector(size_t n, const T& val = T()) {
			resize(n, val);
		}
		vector(int n, const T& val = T()) {
			resize(n, val);
		}
		void swap(vector<T>& v) {
			std::swap(_start, v._start);
			std::swap(_finish, v._finish);
			std::swap(_endofstorage, v._endofstorage);
		}
		vector<T>& operator=(vector<T>v) {
			swap(v);
			return *this;
		}
		~vector() {
			if (_start) {
				delete[]_start;
				_start = _finish = _endofstorage = nullptr;
			}
		}
		iterator begin() {
			return _start;
		}
		iterator end() {
			return _finish;
		}
		const_iterator begin()const {
			return _start;
		}
		const_iterator end()const {
			return _finish;
		}
		size_t size()const {
			return _finish - _start;
		}
		size_t capacity()const {
			return _endofstorage - _start;
		}
		T& operator[](size_t pos) {
			assert(pos < size());
			return _start[pos];
		}
		const T& operator[](size_t pos)const {
			assert(pos < size());
			return _start[pos];
		}
		void reserve(size_t n) {
			if (n > capacity()) {
				size_t old = size();
				T* tmp = new T[n];
				if (_start) {
					for (size_t i = 0; i < old; i++) {
						tmp[i] = _start[i];
					}
					delete[]_start;
				}
				_start = tmp;
				_finish = _start + old;
				_endofstorage = _start + n;
			}
		}
		void resize(size_t n, T val = T()) {
			if (n > size()) {
				reserve(n);
				while (_finish < _start + n) {
					*_finish = val;
					++_finish;
				}
			}
			else {
				_finish = _start + n;
			}
		}
		void push_back(const T& x) {
			if (_finish == _endofstorage) {
				size_t newcapacity = capacity() == 0 ? 4 : capacity() * 2;
				reserve(newcapacity);
			}
			*_finish = x;
			++_finish;
		}
		void pop_back() {
			assert(size() > 0);
			--_finish;
		}
		iterator insert(iterator pos, const T& x) {
			assert(pos >= _start && pos <= _finish);
			if (_finish == _endofstorage) {
				size_t len = pos - _start;
				reserve(capacity() == 0 ? 4 : capacity() * 2);
				pos = _start + len;
			}
			iterator end = _finish - 1;
			while (end >= pos) {
				*(end + 1) = *end;
				--end;
			}
			*pos = x;
			++_finish;
			return pos;
		}
		iterator erase(iterator pos) {
			assert(pos >= _start && pos < _finish);
			iterator it = pos + 1;
			while (it < _finish) {
				*(it - 1) = *it;
				++it;
			}
			_finish--;
			return pos;
		}

	private:
		iterator _start = nullptr;
		iterator _finish = nullptr;
		iterator _endofstorage = nullptr;
	};
	void print_vector(const vector<int>& v) {
		for (auto e : v) {
			cout << e << " ";
		}
		cout << endl;
	}
}